1. Field of the Invention
The present invention relates to dowels used in the woodworking industry to secure two pieces of wood or wood-like material together. In particular, the present invention relates to novel dowels made of a thermosetting resin, a process for making such dowels, and methods of using such dowels.
2. Background of Related Art
In manufacturing cabinets, furniture, and other articles from wood or wood-like material, adjoining pieces of wood are often held securely together with dowels and an adhesive, such as woodworking glue. Conventionally, dowels have been made of wood. Wood costs have increased substantially in recent years and, in turn, the cost of wooden dowels has increased.
In conventional woodworking practice, receiving cavities are formed in each of the respective pieces of wood or wood-like material that are to be adjoined. When the pieces of wood or wood-like material are assembled, glue is typically injected into the dowel receiving cavities. Dowels are then inserted into the cavities and held there by the glue. Alternatively, pre-glued dowels may be employed. Water is typically applied to the dowel cavities and the dowels are moistened to activate the glue as the dowels are inserted into the cavities. U.S. Pat. No. 5,338,569 (Hatch).
It has been suggested to make dowels from thermoforming plastic materials, but such dowels are typically incapable of adhering to the glues used in the woodworking industry. Thus, plastic dowels have heretofore required surface features that create a frictional engagement with the wood into which the dowels are inserted. This frictional engagement may not result in nearly as much bonding strength as is obtained with wood dowels that are glued in the cavities. Thus, thermoplastic dowels have not been widely used in the commercial manufacture of furniture and other articles from wood.
Materials such as fiberboard are able to adhere to glues that have conventionally been employed in the woodworking industry.
Medium density fiberboard ("MDF" or "MDFB") and high-density fiberboard ("HDF" or "HDFB"), which have been conventionally referred to as particle board, include wood chips and, thus, conserve wood by employing wood scraps that are by-products of other wood processing or recycled wood. Typically, particle board has a density of about 45 lbs/ft.sup.3 to about 55 lbs/ft.sup.3. Due to high wood or cellulose content, fiber boards have similar properties to those of wood. While the densities of these materials are about the same or even greater than those of some types of woods, the strengths of these materials and, thus, the strength with which a dowel made from these materials secures two pieces of wood or wood-like material together is typically lower than that of some types of wood.
Fiberboard, including MDF and HDF, may be fabricated from particles, pieces or chunks of wood of mixed characteristics, and a resinous binder material. U.S. Pat. No. 4,857,252 (hereinafter "the '252 Patent"), issued to Melchior et al. on Aug. 15, 1989, discloses an exemplary process for fabricating fiber board. The process disclosed in the '252 Patent includes processing a wet mixture of thermosetting resin and paper, cardboard, or kraft fibers under caustic conditions through a paper machine to provide a sheet of the mixture including 95-98% solids, then subjecting the mixture to a high temperature to dry the mixture and cure the thermosetting resin. The process of the '252 Patent is time-consuming, requires expensive equipment, and is not useful for fabricating relatively thick layers of dense composite material and, in turn, is not useful for making dowels.
Accordingly, there is a need for a dowel that has comparable strength and comparable adherence to adhesives as wood dowels. There is also a need for a process of fabricating dense composite products with these properties suitable for use as a dowel.